• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1049-1052
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• 1997

The pupose of this study on the surface finishing is to examine the performance of brushing as a means of reducing the surface roughness of the precision theaded shafts in ball screw assemblies. Ball screws provide superior performance compared to other types of screw feeds in terms of static and dynamic rolling resistance,backlash,and wear characteristics. The Reduction of the surface roughness of the lead shaft in ball screw assembiles is essential for precision movement,high speed/low noise tracel, and for low wear/long life. To reduce machine dependent errors that would influence the surface roughness compared with other lapping or polishing techniques,experiments will be performed using special wire brushes to polish precision ground shafts. The best results were obtained using the Al /sab 2/O /sab3/ brushes, with the Al /sab 2/O /sab3/ #500 grit brush producing a surface finish of approximately 0.7 .mu.m, and the Al /sab 2/O /sab3/ #600 grit producing a surface finish of approximately 0.8 .mu.m. Both of these results were produced at the highest wheel polishing speed of 3520 rpm. The SiC #500 brush produced a surface roughness of approximately 1 .mu.m at 3520 rpm.

• Korean journal of food and cookery science
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• v.6 no.2
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• pp.105-119
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• 1990

A study on the dietary habit and the food perference of Pre-school Children was made in order to identify the state of their dietary life and provide the data of dietetic education which can help the children to live a desirable food life, by analysing the present dietry life into the dietry habits, food preference, the actual condition of nutrition intake and table manners. 1. The Diet Habits. Both boys and girls were fond of dinner best and tended to neglect breakfast and lunch. 64.2% of the total children took meals regularly. 2. Food Preference. The most favorite food was beef, ham, Dupoo (beancurd), squid, ice-cream, bananas, watermelon, sweet potatoes, corn, Ingeolmi (cake form glutinous rice), doughnuts, JJajangmyon (Chinese noodles), Coke, fried chicken. 3. The Actual Conditions of Nutrition Intake. The frequency of intake of meat and its processed food was the lowest and that of fishes, shellfishes, fats and vegetables was low, too. 4. Table manners and Sanitary Conditions. The average mark of table manners and sanitary conditions is 12.49${\pm}$2.65. The children didn't practice well in the following points; talking at table, beginning to eat after the beginning of elder person's, brushing their teeth after taking meals, keeping a straight posture.

• Korean journal of applied entomology
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• v.20 no.1 s.46
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• pp.21-24
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• 1981

This study was conducted to obtain a supply of conidia sufficient for screening mungbean mutant lines for a source of resistance to Cercospora leaf spot caused by Cercospora canescens Ellis and Martin. Abundant sporulation occurred in cultures on mungbean leaf decoction oatmeal agar(MOA) exposed to about 2,500 Lux of fluorescent light. but it did not occur in continuous darkness. The conditions that produced maximum number of conidia was not coincided with those for vegetative growth and pigmentation in culture medium. Removal of aerial mycelium in culture by brushing with sterile water so enhanced the conidial production that oatmeal agar medium(OA) could be useful for production of abundant conidia by the treatment.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.577-583
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• 2012

Objectives : The purpose of this study was to examine the oral health promotion behavior in dental hygiene students and other major students Methods : Questionnaire survey was carried out targeting 222 dental hygiene students and other major students. The collected data was performed frequency & percentage, chi-square test and multiple regression analysis. Results : The oral health awareness is male and female all 'unhealthy' 39.3%, 39.4%. dental hygiene students and other major students 41.9%, 38.5%(p<0.05). Oral health promotion behavior results, dental hygiene student who is higher than the other major students certificate in oral health education 66.2%, regular dental check-up 81.1%, use of oral hygiene supplies 54.1%, brushing three times a day 79.1% (p<0.05). The affecting factors on the oral health promotion behavior of dental hygiene students were use of oral hygiene supplies, explained 20.8%(p<0.001). The affecting factors on the oral health promotion behavior the other major students were regular dental check-ups, explained 20.1%(p<0.001). Conclusions : To promote the oral health of university students oral health education should be provided. Importance of dental check-up, recommendation for the use of oral hygiene supplies, etc. The findings of this study were oral health education should be strengthened for them.

• Journal of Korean society of Dental Hygiene
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• v.15 no.3
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• pp.505-512
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• 2015

Objectives: The purpose of this study was to compare the oral health behavior in adolescents between multicultural and ordinary Korean families. Methods: The subjects were 66,797 adolescents who were derived from the web-based survey of the National 2014 Korean Youth Risk Behavior of Korean Center for Disease Control. A self-reported web-based questionnaire survey was carried out from June 1 to 30, 2013. A multicultural family is defined as the immigrant mother and child in the study. The variable included demographic, socioeconomic, and oral health related behavior. The demographic characteristics included sex, age, residence area, subjective academic achievement, type of family, education of parents, subjective economic status, and nationality before marriage. Data were analyzed by PASW statistics 18.0. Results: Tooth brushing frequency was closely related to family type, age, residence area, academic achievement, residential type, education level of the parents, and economic status. Conclusions: It is necessary to support oral health services and oral health promotion programs for the adolescents in the multicultural family.

• Journal of Korean society of Dental Hygiene
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• v.15 no.4
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• pp.593-602
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• 2015

Objectives: The purpose of the study is to investigate the relations between oral health status and subjective oral health recognition in Korean adolescents. Methods: The survey data were extracted from the 2012 Korea National Oral Health Survey from June to November, 2012. The survey consisted of oral checkup data and the oral health interviewing data of 9,981 adolescents(5,335 male, 4,646 female) by proportional distribution. The questionnaire included general objective oral health status and subjective oral health recognition. The subjective oral health recognition consisted of general characteristics of the subjects, oral health status, oral health behavior, and subjective oral health recognition. Results: According to multiple regression analysis for the relations between general characteristics and subjective oral health recognition, subjective health recognition, the influencing factors were gender, age, the number of tooth brushing per day, intake of snacks and carbonated drinks, regular oral examination, decayed teeth (DT), missing teeth (MT,) and DMFT. Conclusions: The routine oral checkup is the most important method to improve the oral health management in the adolescents. The continuing oral health improvement project must be implemented based on the law and will keep the adolescents in good oral health status.

• Journal of Korean society of Dental Hygiene
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• v.15 no.5
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• pp.813-821
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• 2015

Objectives: The purpose of the study was to investigate the relationship between health behavior and oral symptoms in Korean adolescents. Methods: The subjects were 72,060 adolescents who were selected from the web-based survey of the 10th (2014) Korean Youth Risk Behavior of Korean Center for Disease Control. Data were analyzed by PASW statistics 18.0. A web-based self-reported questionnaire was completed by 74,167 middle and high school students. The subjects consisted of 36,470 boy students (52.2%) and 35,590 girl students (47.8%) from 400 middle schools and 400 high schools. Results: Multiple logistic regression analysis revealed that experience of oral symptoms were related with sex, age, academic achievement, economic status, alcohol drinking, moderate physical activity, muscular strength exercises, walking, fruit consumption, milk consumption, fast food consumption, snack consumption, daily tooth brushing frequency, use of fluoride toothpaste, school based oral health education, dental sealant and dental scaling. Conclusions: There were close relationship between heath behavior, oral health behavior, and experience of oral symptoms. To improve the health promotion for the adolescents, oral health program development and primary prevention strategy must be established.

• Journal of Korean society of Dental Hygiene
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• v.7 no.1
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• pp.31-39
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• 2007

This purpose of this study was to provide the basic data for preventing dental caries, and maintaining and enhancing Oral health education. The subject of this study through the survey of the recognition of Oral health education, a questionnaire survey and dental experience and Pit and fissure sealant status was conducted for 334 male and female students who were in the 4th, 5th, 6th grade of elementary school in Ulsan city. Statistical analysis was conducted using the SPSS 11.5 with t-test, ANOVA and correlation. The obtained results were as follows 1. Experience caries on permanent teeth was male score of 58.0% and female score of 42.0% and an everage score of 52.7% very low. 2. The students who were in the 4th, 5th, 6th grade of elementary school Experience caries on permanent teeth is grad higher(p=0.000). Pit and fissure sealant of teeth number and teeth surface status by grad higher(pE0.016, p=0.000). 3. Oral health knowledge and behavior is significantly related to status(p=0.001), behavior and Daily tooth brushing frequency was significantly related to status(p=0.000). But experience caries on permanent teeth and Oral health knowledge and behavior beween wasn't significantly related to status.

• The Journal of Korean Society for School & Community Health Education
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• v.10 no.2
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• pp.85-94
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• 2009

Objectives: This study was conducted to improve dental health regarding behavior and understanding of dental health of day care teachers by analyzing actual dental health state. Methods: This study was performed from October 1 to October 30, 2008 for 194 teachers who worked at nurseries in Daegu. Results: In the toothbrushing recognition, 42.3% of the said that tooth brushing after eating is necessary but only 26.3% had the children bush teeth. They did not have the children brush the teeth because they did not have enough time. Many teachers (75.3%) said that dental caries could be prevented. But only 4.1% of them said that fluorine is effective for the prevention of dental caries. The preschool teachers had dental health education experience, better understood the importance of dental health education than those who did not have(p < 0.05). Conclusion: The preschool teachers who had dental health education better recognized the importance of dental health education.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.72-77
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• 2005

The materials used in a ship screw propeller are commonly made with brass. The seawater corrosion and seawater cavitation of the screw propeller reduces the propulsive performance of the ship. In screw manufacturing, the corrosion rust of the screw propeller is removed through a hand grinding method. The grinding process produces dust of the heavy metals from the brass. The dust creates a poor working environment that is harmful to the health of the workers. An automatic corrosionrust removing apparatus, using a blasting method, was developed for the improvement of screw polishing conditions and its working environment. The performance of this apparatus was investigated by surface roughness, weight loss rate, hardness, electrochemical corrosion resistance, and cavitation erosion, after removing of the corrosion rust under various blasting conditions. Two medias of alumina and emery were used in this experiment. The surface roughness and hardness of the screw were improved by this apparatus. The electrochemical corrosion potential (Ecorr) and current density (Icorr) were measured by the dynamic polarization method, using a potentiostat,under the conditions of surface polishing with grinding, blasting, wire brushing, and fine sand papering. The test results prove that the new corrosion rust-removing apparatus improves the surface performance of a screw propeller.